The purpose of this research study is 1) To identify cancers cells with low oxygen (hypoxic cells) 2) To study the relationships between such hypoxic cells and the growth and spread features of cancer cells and 3) To monitor the side effects of pimonidazole. It is known that hypoxic cells can survive the damaging effects of radiation. This could be one reason why some cancers are not cured by radiation therapy. We would like to study whether hypoxic cells are associated with a greater risk of the spread of cancer cells. Information from this type of study will improve our understanding of cancer and cancer treatment.